5. HIPÓTESIS
1.4. DESVINCULACIÓN DE FUNCIONARIOS DE CARGOS DE CARRERA
2.5.1 Methods
A telephone survey of NZ PHSs was undertaken in March 2007 to assess current methods of gathering enteric disease notification surveillance data (Figure 9). The core questions asked were:
• What method do you use to follow up notified cases of campylobacteriosis?
• What method do you use to follow up other common enteric disease notifications?
• If you use a postal questionnaire what is your return rate? (If it was not measured they were asked to estimate the response rate).
Services who indicated they used a postal questionnaire were also asked to forward a copy of the questionnaire to MCPHS.
2.5.2 Results
The telephone survey undertaken in March 2007 highlighted the differing approaches taken for gathering of enteric disease surveillance data entered into EpiSurv (Table 2). The data collection methods used included the following: sending educational advice only by post; sending postal questionnaires - including educational advice; telephone interviews; or face to face interviews with cases. The data collection methods within some PHS were difficult to record as some had no consistent data collection method e.g. the HPO responsible for a geographical area within the PHS could follow up notifications in their area in whichever way they chose. This meant there was no one consistent method within some PHS where multiple HPOs were responsible for surveillance.
There was also variation in how questions regarding potential risk factors were completed. Some PHSs asked about all the risk factor fields and others just completed the section identified by the case as the likely source. Some of the PHSs interviewed forwarded high risk cases (i.e. food workers or all of the common enteric disease notifications) to their local territorial authorities (TLA).
During the interviews no PHS indicated that response rates to postal questionnaires were measured in any formal way. Six of the PHSs interviewed estimated the percentage of questionnaires they thought were returned. Three estimated the return rate for their region was between 60 to 70% and three estimated between 50 to 60%. Seven questionnaires were forwarded to MCPHS from regional PHSs. The length of the questionnaires varied from two to seven pages, with three of the seven being four pages in length. A one page pre-screen questionnaire received from Regional Public Health (RPH) in Lower Hutt was identified by the project steering group as the most useful format to be adapted for the questionnaire trial. The benefits of the RPH questionnaire were that in a clear lay out on a single page it gathered the majority of the information required to complete an EpiSurv CRF. The questionnaire could easily be adapted with the addition of a second page making it possible to include all the questions required to complete a CRF and give room for any additional comments.
Table 2: Results of survey of NZ PHS identifying data collection methods for notified cases of common enteric disease
PHS Notified Campylobacter Trigger point* Action if triggered* Notified Giardia Notified Cryptosporidium Notified Salmonella Notified Yersinia PHS Northland TI TI TI TI TI ARPHS Auckland AP FC, IN PQ AP AP AP AP PHS Waikato
AP TI, VI TI, VI TI, VI TI, VI
PHS Toi Te Ora AP HRG TI TI TI TI TI PHS Tairawhiti PQ HRG, IN, FC PQ VI VI VI PHS Taranaki
PQ HRG TI then PQ TI then PQ TI then PQ TI then PQ
PHS Hawkes Bay PQ HRG PQ PQ PQ PQ MidCentral PHS Palm Nth PQ IN,HRG,FC TI TI TI TI MidCentral PHS Whanganui
PQ HRG TI then PQ TI then PQ TI then PQ TI then PQ
RPH Lower Hutt AP >50 per week** PQ AP AP AP AP RPH Wairarapa AP HRG AP AP AP AP PHS Nelson/Marlborough AP TI TI TI TI CPH Christchurch PQ HRG, IN, FC PQ PQ PQ PQ CPH Greymouth
PQ IN TI PQ, VI, TI PQ, VI, TI PQ, VI, TI PQ, VI, TI
CPH Timaru
TI, PQ TI TI TI TI
Public Health South Dunedin
TI, PQ TI, PQ TI, PQ TI, PQ TI, PQ
Public Health South Invercargill
TI, VI TI, VI TI, VI TI, VI TI, VI
Key
Advice by Post AP Telephone interview TI
High Risk Group HRG Food Complaint FC
Increase in notifications IN Postal Questionnaire PQ
Visit VI
* Six of the 17 PHSs did not follow up notifications of campylobacteriosis routinely. However, some had clearly defined trigger points when further investigation of sporadic cases would be undertaken
2.5.3 Discussion
A review of other PHS systems allowed the most appropriate systems for use within the project to be considered and identified clear differences in the approaches for gathering common enteric disease surveillance within PHSs nationally.
A true response rate for postal questionnaires could not be identified, but estimates were received from those using questionnaires that we could expect between 50 – 70 percent return rate during the trial. This was used to estimate the potential response rate for the postal questionnaire trial.
Larger PHSs have staff who specialise in work associated with communicable disease notifications. Smaller PHSs did not always have consistent surveillance methods within their own region; their HPOs work as generalists and are responsible for all types of work in the PHS within a specific geographical area. Other work undertaken by a generalist HPOs included: commenting on resource consents; health and safety within early child care centres; food complaints; emergency management; outbreak management and biosecurity. Generalist HPOs can then choose to follow up notifications by whichever method they deemed suitable for the time available and the geographical area they are were responsible for.
One of the PHSs who used a number of TLAs to follow up notifications expressed concern that forwarding notifications to TLAs resulted in further filtering of the information from cases and that quality and completeness of follow up varied greatly between different TLAs in their region.
The differences highlighted in Table 2 and discussed above show that between the PHSs there are many different methods of data collection for notified cases of common enteric disease. Potentially this could mean an individual with campylobacteriosis (or any other common enteric disease) in one part of NZ may have no contact with their local PHS, whereas somebody with the same disease in another part of NZ could receive a visit from an HPO and be interviewed in their home. Overall the result is huge variations in the methods used to gather surveillance data for notified cases of common enteric disease. This ultimately affects the quality of data and potentially results in biased conclusions formed by researchers using the data at a local, national or international level.